(1) Shortcut (also including recall)
Cutting off some annual branches or perennial branches during pruning is called short cutting (usually cutting off annual branches is called short cutting, and cutting off perennial branches is called retraction). Shortening annual branches can promote the germination of lateral buds under the incision, thus promoting the branch to expand the crown. Short cutting of perennial branches can promote the regeneration and rejuvenation of trees, enhance the vitality of trees and delay aging. Short cutting is very important in the pruning of hazelnut trees. It can be said that there is no normal growth and development of hazelnut trees without short nodes. The most representative nutritional index of hazelnut tree is the length of annual branches. The growth state of annual branches not only indicates the strength of tree potential, but also determines the yield. The annual branches of hazelnut tree are the basis of fruiting, which is closely related not only to the yield of the current year, but also to the formation of flower buds and the yield of the next year.
This reaction varies with the degree of truncation. In a certain range, the heavier the short cut, the greater the growth of single branch, but the overall growth of short cut branches is relatively reduced. Short cutting can reduce the total number of branches and buds, improve the nutritional status of trees, and help to enhance tree vigor, but overweight short cutting will affect the total growth of trees.
Light cutting and short cutting: cut off less than 30% of the length of annual or perennial branches. Light and short cuttings are mainly used for rejuvenation of fruiting mother branches and expansion and growth of perennial branches. Light and short annual branches have long branches, a large number of lateral buds and scattered nutrients, which can not only bear fruit, but also expand the crown. Light and short pruning is an important pruning method for expanding the crown and early fruiting of young hazelnut trees, with less pruning and less loss of total branches.
Medium and short shears: cut off 30-50% of the length of annual or perennial branches. It is to cultivate large-scale fruiting branches, annual branches, medium and short pruning where there is space, increase the number of branches, and cultivate large-scale fruiting branches.
Heavy and short cutting: cut off 50-80% of the length of annual or perennial branches. Mainly aiming at the pruning method of regeneration of fruiting mother branches and weak main branches of hazelnut trees in full fruit period. The main pruning task of hazelnut tree when it enters the full fruit stage is to cultivate fruiting branches and rejuvenate the tree, which needs to be done by pruning annual or perennial branches.
Retraction: cut off a part of the branches that are more than 2 years old, that is, cut off the branches that are more than 2 years old. Retraction can control the development of the crown or main lateral branches, adjust the angle and orientation, improve the illumination, rejuvenate and renew the branches, and prolong the fruiting period. Retraction is mostly used for backbone branches and soft long slow-release branches, which makes the big branches and long branches shorter, stronger and thicker and enhances the bearing capacity. It is also used for the cultivation of branches and the regeneration and rejuvenation of aging trees. Retract pruning should pay attention to the amount of pruning. A certain degree of retraction is beneficial to restore the tree potential. Too much retraction cuts off too many branches, which breaks the balance between the ground and the ground of the tree and is not conducive to the growth of the tree.
(2) refinement
Pruning from the base of annual or perennial branches is called thinning. Thinning can adjust the density and distribution of branches, increase space, improve ventilation and light transmission conditions, enhance the photosynthetic efficiency of leaves, balance the tree potential, slow down growth, concentrate the nutrients of trees, and promote the growth and enrichment of branches. Thinning can promote local area, reduce the number of branches and total leaf area, affect the thickening growth of mother branches, weaken the growth of the whole tree and reduce the total growth of the tree. Thinning can inhibit the growth of branches in front of the wound and promote the growth of branches behind the wound. Hazelnut trees tend to be weak in the back and upper parts because of their thick base branches, and the big branches are sparse on the backbone branches, which is easy to cause the tree to be weak.
Therefore, when pruning fruit trees, the big branches that should be thinned should be avoided from the base, and a "nutrient thinning branch" with a length of more than 20cm should be left. After a period of "nutrition dredging", the branches in front can get more nutrition, which really plays a role in concentrating nutrition. Otherwise, the wound at the base will hinder the upward movement of nutrients in the tree and weaken the growth of the front branches.
(3) slow release
Just don't cut branches. The robust fruiting mother branches and large fruiting branches of hazelnut trees are basically not cut. Only by maintaining a certain number of slow-release branches can the yield be formed, and the yield can be delayed for several years. After the seed-setting ability decreases, new fruiting mother branches can be formed by pruning and thinning. The effect of slow release also relieves the tree potential, and after slow release of branches, it can also open corners and improve the light.
The fruit of hazelnut tree mainly depends on the axillary buds of annual slow-release branches. If there are many annual branches left during pruning, the yield will be more in that year, or even higher for several years in a row. Hazelnut trees mainly bear fruit by slow-release fruiting mother branches at the young stage.
Sparse planting density
The planting distance is generally not less than 3 meters, and the farthest is not more than 6 meters, but considering the early high yield, it can be properly planted closely.
Early high yield density 1, plant spacing 2× 3m, yield per mu 1 1 plant (667m2); 2. Plant spacing: 2× 2m, (667 m2) 166 plants per mu. These two densities should be adjusted by pruning and transplanting when the crown is closed, which affects growth and yield.